There are situations in which presenters desire the aid of scripts or cues that are visible to themselves, but not to their audience or camera capturing their presentation. Typically, the intent is to make the speech, performance, or other presentation appear spontaneous or well-rehearsed, and not something conspicuously being read or directed. In the past, teleprompters or cue cards have been used for this purpose. Unfortunately, these approaches have a number of shortcomings. Notably, it is difficult to position the teleprompter or cue card in a location that is simultaneously viewable by the presenter, but undetectable by the audience in a way that enables the presenter to maintain the appearance of presenting without external aids.
Some teleprompters, such as those used by politicians when making speeches, utilize a pane of glass positioned at the top of a stand at an angle such that the presenter standing directly in front of the pane of glass can see the words projected onto the front side of the glass. However, the projected words are not visible when viewed from behind the pane of glass. The audience positioned behind the teleprompter is able to see the teleprompter, including the pane of glass, but the words projected onto the glass are not visible. As a result, the audience is aware that the speaker is likely using the teleprompter because of its presence in front of the speaker, but the audience is unable to see what is being displayed to the speaker. Anyone positioned to see the front of the front side of the pane of glass would be able to see both the teleprompter as well as the displayed text, just as it is seen by the speaker.